Diffusion transfer product and process containing 5-seleno-1,2,3,4-tetrazole

ABSTRACT

Seleno tetrazoles such as 1-phenyl-5-seleno-1,2,3,4-tetrazole, 1-allyl-5-seleno-1,2,3,4-tetrazole, etc. are used as toners in a diffusion transfer process. The toner can be incorporated in the receiving sheet or in a processing solution. These toners are particularly useful when employed in a diffusion transfer process to improve the stability of the toned image.

United States Patent Parsons {451 Apr. 11, 1972 [54] DIFFUSION TRANSFERPRODUCT AND [56] References Cited PROCESS CONTAINING S-SELENO- UNITEDSTATES PATENTS l,2,3,4-TETRAZOLE 2,699,393 l/l955 Weyde ..96/58Inventor: Tlmothy Parsons, Hilton, NY. 3,305,362 2/1967 Riester et al...96/61 M [73] Assignee: gaztman Kodak Company, Rochester, PrimaryExaminer Norman G- Torchin Assistant Examiner.lohn L. Goodrow [22]Filed: Jan. 14, 1970 AttorneyW H. J. Kline, B. D. Wiese and Henry E.Byers [21] App]. No.: 2,964 57 ABSTRACT Seleno tetrazoles such asl-phenyl-S-seleno-l ,2,3,4-tetrazole, U-S. w u96/29, l al]yl 5 seleno lz 3 4 tetrazole etc are used as toners in a [51] Int. Cl ..G03C 5/54diffusio transfer process, The toner can be incorporated in [58] Fieldof Search ..96/29, 52, 58 the receiving sheet or in a processingsolution. These toners are particularly useful when employed in adiffusion transfer process to improve the stability of the toned image.

14 Claims, No Drawings BACKGROUND OF THE INVENTION This inventionrelates to receiving layers employing seleno tetrazoles and to diffusiontransfer processes employing these receiving layers and also employingseleno tetrazoles to improve the tone of images obtained by a diffusiontransfer process.

Diffusion transfer processes are well known. For example, Rott, U.S.Pat. No. 2,352,014 describes such a process wherein undeveloped silverhalide of an exposed photographic emulsion layer is transferred in asilver complex imagewise by imbibition to a silver precipitating ornucleating layer, generally to form a positive image therein. The silverprecipitating or nucleating layer generally comprises a bindercontaining nuclei such as nickel sulfide, colloidal metal or the like.

In carrying out the diffusion transfer process, there have been manyproblems involved in obtaining a satisfactory image. For instance, manyof the prints have a brownish image, lack stability, etc. Therefore,various methods have been proposed to improve the process such asincorporation of toning agents in the processing solution, substitutionof various silver precipitants, incorporation of quaternary salts, etc.

In order to improve the tone of diffusion transfer images, it is knownto use phenyl mercapto tetrazoles such as those disclosed in U.S. Pat.No. 2,699,393. However, there have been problems involved with thestability of the prints obtained using these particular tetrazoles.Moreover, there has been a problem of obtaining satisfactory tone withcertain binding materials used for coating the receiving sheet in whichare dispersed a silver precipitant such as silver precipitating nuclei.For instance, proteinaceous colloids such as gelatin have beenrecognized as particularly useful binders for these silver precipitants.However, using gelatin as a vehicle for silver precipitants such asnuclei, and special types of nuclei such as colloidal silver, results inprints having a yellow to light brown color.

The problem of obtaining a desirable tone using a proteinaceous colloidsuch as gelatin has been recognized in the art and various attempts havebeen made to overcome this problem, as can be seen by Land et al. U.S.Pat. No. 2,774,667, issued Dec. 18, 1956, which describes the use ofasilica matrix for silver precipitating nuclei such as colloidal silverto avoid having the prints result in a yellow or light brown color.

It is recognized that a toning agent resulting in a neutral or blackimage which would be operative with a proteinaceous binder would be veryuseful in diffusion transfer processes. It is also recognized that itwould be desirable to have a toner which could be applied either in thedeveloping agent or which could be incorporated satisfactorily in thereceiving sheet itself.

SUMMARY OF THE INVENTION In accordance with this invention, it has beenfound that a receiving element for use in the diffusion transfer processcomprises a seleno tetrazole toning agent. The seleno tetrazole toningagent may be present in a developer or activator solution when thediffusion transfer process is carried out or in the silver halideemulsion provided the seleno tetrazole is present at the time offormation of the image in the receiving sheet. The seleno tetrazole isused in amounts of about 0.01 to about 1.0 g. per liter of developing oractivating solution, about 0.01 mg. to about 0.5 g. per ft in thereception layer.

The following seleno tetrazoles are included among those found to besuitable for the purpose defined above; seleno tetrazoles substituted byaliphatic residues, as for example, 1- all'yl5-seleno-l,2,3,4-tetrazole,seleno tetrazoles substituted by aromatic or heterocyclic residueshaving 1 to 12 carbon atoms' as for example, lphenyl--seleno-l,2,3,4-tetrazgle.

The following formula illustrates suitable 5-seleno-l,2,3,4- tetrazoles:

R represents alkyl having one to 10 carbon atoms such as, for example,methyl, ethyl, propyl, butyl, etc., aralkyl (one to 10 carbon atoms)such as benzyl, etc., alkenyl (one to 10 carbon atoms) such as, forexample, allyl, etc., aryl such as, for example, phenyl, tolyl, etc.

Additional advantages may be obtained by incorporating in the receivingsheet other materials such as a polyvinyl quaternary salt, an iodide,other toners, or a silver salt such as e.g. silver nitrate.

A receiving element described above is used advantageously to provide aphotographic print having an image in a receiving layer on a support bya photographic silver salt diffusion transfer process.

DESCRIPTION OF PREFERRED EMBODIMENTS In one embodiment of thisinvention, colloidal noble metal nuclei are dispersed in a proteinaceousbinder such as gelatin containing a polyvinyl quaternary salt such aspoly( l-methyl- 4-vinyl pyridinium methylsulfate), potassium iodide andlphenyl-S-seleno-l,2,3,4-tetrazole, after which the mixture is coated ona suitable support such as paper. After drying, the receiving sheet canthen be used in a diffusion transfer process and results in an image ofgood tone and density.

In another embodiment of this invention, colloidal nuclei are dispersedin a binder as described in the above embodiment and the compositioncoated on a suitable support such as paper. After drying, an unhardenedsilver halide emulsion is coated over the receiving layer. Particularlyuseful emulsions are described in Yackel et al. U.S. Pat. No. 3,020,155.The exposed photographic element is processed using a silver halidedeveloping solution containing a silver halide solvent such as sodiumthiosulfate. The undeveloped silver halide, complexed with thiosulfate,diffuses to the nucleated underlayer where an image is formed in thesilver halide emulsion. Unhardened silver halide emulsion is thenremoved by washing with warm water.

The binder for the silver precipitant can be substantially protein andtypically at least 50 percent, by weight, of a protein as describedherein. Gelatin is a particularly useful binder, but other proteins suchas casein, zein, albumin, etc., may be used.

In another embodiment, a reduced level of process stain is obtained byreducing the amount of the colloid binder such as gelatin or some otherprotein so that not more than 15 mgs./ft is coated on the support. Thisresult in a coating of about 0. 10 to about 0.20 micron in thickness.

Gelatin and other proteins may also be admixed with compatible polymers.Polymers which are particularly useful includeterpoly(ethylacrylate-acrylic acid-Z-acetoxyoxyethyl methacrylate), etc.

Polymers particularly useful as water-soluble polyvinyl quaternary saltsare described in VanHoof et al., U.S. Pat. No. 3,174,858 issued Mar. 23,1965. These water-soluble basic polymeric quaternary salts have apolyvinyl chain having two to 10,000 monomeric units, at least monomericunit monomerinuit of which is linked to a five or six memberedheterocyclic nucleus containing a hetero-quaternary nitrogen atom.

In one embodiment, the polymer has the following structure:

l l Ton CHZI N r R e in which n is an integer from two to 10,000 and Xis any suitable anion such as CH SO e, para toluene sulfonatee, iodide,etc. R represents H, an alkyl group having one to 10 carbon atoms suchas, for example, methyl, ethyl, propyl, butyl, etc., halogen, N NH a,aralkyl, aryl, etc. R is selected from the same group as R, but can be adifferent group than R. It will be appreciated, of course, that theheterocyclic nucleus can contain additional hetero atoms and that thering may be substituted with other groups as R above. The substituentscan be the same or different.

Typical polymeric materials include poly(l,2-dimethyl-- vinylpyridiniummethylsulfate poly( 1 -methyl-2-vinylpyridinium iodide), poly(l-methyl-2-vinylpyridinium methylsulfate), poly)l-methyl-4-vinylpyridinium iodide), poly( l methyl-4-vinylpyridiniummethylsulfate), poly(l-vinyl-3- methyl imidazolium iodide) and poly(l-vinyl-3-methyl imidazolium methylsulfate).

In another embodiment, in which the polyvinyl chain has attached theretoat least one monomeric unit linked to a hetero cyclic nucleus containinga hetero-quaternary nitrogen atom, the chain can contain attachedthereto at least one linear group. In preparing a typical polyvinylquaternary salt, the polymerization mixture can contain a linearcompound such as N-cyanoacetyl-N-methacrylylhydra2ine (described in US.Pat. No. 2,940,956),

2-acetoacetoxyethyl methacrylate, described in US. Pat. Application Ser.No. 525,272 filed Dec. 20, 1965 in the name of Donald A. Smith, entitledPhotographic Materials, issued as Belgian Pat. No. 691,446.

In a particularly useful receiving layer, we employ from 0.1 to 80mg,/ft preferably 0.2 to about 5 mg./ft In a typical embodiment, 30 mg.of the polyvinyl polymer are used for l g. of gelatin in the receivinglayer.

In addition to binder combinations which include a proteinaceousmaterial combined with a synthetic polymer, we can use a substantiallyprotein free receiving layer, comprising a colloid binder and a silverprecipitant. In one embodiment a colloid binder comprises at least 90percent by weight of a copolymer (1) about 90 percent to about 98percent by weight, of at least one haloalkyl methacrylate in which thehaloalkyl group contains one to carbon atoms with (2) about 2 percent toabout 10 percent by weight, of an unsaturated polymerizable organic acidhaving three to six carbon atoms.

In the event that an integral diffusion transfer element is desired inwhich a silver halide emulsion is coated over a receiving layer on asupport, it is particularly useful to employ a polymeric binder such asa latex binder for the nuclei. For example, a styrene-butadiene latexmay be used such as one having a 65/35 molar composition at aconcentration of 50 percent by weight solids. Various other latices ofvinyl or acrylic homoor copolymer may be used. After the latex coatingcontaining a silver precipitant has been prepared in a suitable support,it can then be overcoated with an unhardened gelatin silver halideemulsion which, after exposure and processing to obtain an image in thereceiving layer, can then be removed by washing with warm water orsimilar means.

In still another polymeric binder type of receiving layer, alkylacrylate-sulfo alkyl polymers are used. Polymers of this type aredescribed in US. Pat. Application Ser. No. 525,272 in the name of D. A.Smith issued as Belgian Pat. No. 691,446. Typical polymers includecopoly(butyl acrylate-sulfopropyl acryIate-Z-acetoxyethyl methacrylate),copoly(butylacrylatesulfopropyl acrylate etc.

An alkaline iodide, such as, e.g., ammonium, guanidine, sodium,potassium, lithium iodide, etc., can be present in the receiver in anamount of about 0.1 to about 20 mgJft, preferably 0.5 to about 10mgJft". The effect of incorporation in certain receiving layers ofiodide is particularly unexpected, since the tone is improved.

The addition of a silver salt or complex such as, e.g., silver nitrate,to certain receiving sheets improves the quality of the transfer, e.g.,the image density. Any silver salt or complex can be used, includingboth organic and inorganic silver compounds. A typical organic silvercomplex is, for example, silver dipyridyl nitrate. Other silver saltsand complexes which are included are described in Gilman et al., US Pat.No. 3,446,619. Still other silver salts of mercaptotetrazole andmercaptotriazles and related heterocyclic mercapto compounds aredescribed in U.S. Pat. No. 2,432,864. However, silver nitrate ispreferred. The silver compound can be used in an amount of about 0.01 toabout 10 mgjft preferably 0.05 to about 5 mg./ft

Coating solutions which contain addenda other than a silver precipitantare also useful in preparing receiving layers. In addition to variouscomponents contained in the coating composition according to thisinvention, surfactants, coating aids, developing agents, release agents,silver halide solvents, etc, may be added to improve the image qualityin the receiving sheet.

Particularly useful surfactants and spreading agents in receivercoatings include saponin, lauryl alcohol sulfate, p-tert octyl phenoxyethoxy ethyl sodium sulfonate, etc.

Suitable silver precipitants for use in the receiving layer includevarious silver precipitating agents known in the art. As examples ofsuitable silver precipitating agents and of imagereceiving elementscontaining such silver precipitating agents, reference may be made toUS. Pat. No. 2,698,237, 2,698,238 and 2,698,245 issued to Edwin H. Landon Dec. 28, 1954, US Pat. No. 2,774,667 issued to Edwin H. Land andMeroe M. Morse on Dec. 18, 1956, US. Pat. No. 2,823,122 issued to EdwinH. Land on Feb. 11, 1958, US. Pat. No. 3,396,018 issued to Beavers etal. Aug. 6, 1968 and also US. Pat. No. 3,369,901 issued to Fogg et al.Feb. 20, 1968. The noble metals, silver, gold, platinum, palladium,etc., in the colloidal form are particularly useful.

Nobel metal nuclei are particularly active and useful when formed byreducing a noble metal salt using a borohydride or hypophosphite in thepresence of a colloid as described in the Rasch US. Pat. ApplicationSer. No. 796,552 filed Feb. 4, 1969. The metal nuclei are prepared inthe presence of a proteinaceous colloid, such as gelatin, and coated onthe receiving sheet. The same or a different colloid may be added, ifdesired. It will be appreciated from the above that the coatingcomposition generally contains not only nuclei, but also reactionproducts which are obtained from reducing the metal salt. Accordingly,it is within the scope of our invention to include in the receivinglayer the reaction by-products which are obtained during the reducingoperation.

The amount of colloid used in preparing the above active noble metalnuclei can be varied depending upon the particular colloid used, e.g.,gelatin, reducing agent employed, e.g., borohydride, proportions ofreagents, etc. Typically about 0.5 percent to about 20, percent byweight, based on the total reaction mixture of colloid is used,preferably from about 1 percent to about 10 percent.

In a particularly useful embodiment, 30 to ,ug/ft of ac tive palladiumnuclei in 80 mg. of colloid (solids basis) is coated per square foot ofsupport. The colloid binder is advantageously coated in a range of about5 to about 500 mg./ft Suitable concentrations on the receiving sheets ofactive noble metal nuclei as disclosed above can be about 1 to about 500ug/ft Other silver precipitants can be coated in a concentration of upto 5 mg./ft

The supports which can be used for coating with the receiving layer areany of those which are suitable and include paper, wood, glass,plastics, etc. A particularly useful support is paper, especially barytacoated paper. However, in a preferred embodiment, a polymeric materialwhich acts as a moisture barrier, such as polyethylene or the like,which is pigmented to provide a white surface is used. Antistain agents,such as acids, etc., can be incorporated in the supports or supportinglayers. Typical antistain agents are disclosed in Yungkurth et al., US.Pat, No. 3,250,619 and Yungkurth, US. Pat. No. 3,326,744. Otherpolymeric materials which may be used as coatings on paper or asself-supporting webs include polyesters, polyamides, polycarbonates,polyolefins, cellulose esters, polyacetals and the like.

In order to obtain adhesion or to improve adhesion to a receivingsupport, treatments of the support, e.g., photographic film base, may becarried out including subbing the support, electron bombardment,treating with peroxide and the like.

The receiving layers of our invention may also have therein particlessuch as silica, bentonite, diatomaceous earth such as Kieselguhr,powdered glass and fullers earth. In addition, colloids and colloidalparticles of metal oxides such as titanium dioxide, colloidal alumina,coarse aluminum oxide, zirconium oxide and the like may be used with thenuclei in the receiving layers.

In carrying out the diffusion transfer process, conventionally a silverhalide emulsion is exposed to a light image after which it is contactedwith a silver halide developing agent containing a silver halidecomplexing agent. The exposed emulsion is developed in the light struckareas and the unexposed silver halide is complexed with the silverhalide complexing agent after which the emulsion is contacted against areceiving sheet and the complexed silver halide diffuses imagewise tothe receiving sheet containing a silver precipitant.

In some instances it may be desirable to treat the receiving sheet inorder to improve the stability of the sheet, particularly with regard tothe silver image thereon. A simple stabilizing method merely involveswashing the print in order to remove any processing chemicals which mayremain thereon. However, the washing step does not protect the printfrom subsequent chemical reactions with oxygen, hydrogen sulfide, etc.,in the atmosphere, which have an adverse effect on the stability of thesilver image. For these reasons, it has been proposed to coat the printwith a coating composition such as that disclosed in US. Pat. No.2,979,477 comprising a mixture of vinylpyridine polymer and ahydantoin-formaldehyde condensation polymer.

Suitable print coating compositions may also employ a polymeric materialsuch as methylmethacrylate-methacrylic acid copolymer or the combinationof an acid group or sulfate group containing polymer such ascopoly(methylmethacrylate-methacrylic acid) and a hydantoin-formaldehydecondensation polymer, such as that disclosed in French Pat. No.1,493,188. A heavy metal salt, such as zinc acetate, may alsoadvantageously be incorporated in the print coating composition. Furtherimprovement is obtained by incorporating in the coating composition anacid, such as acetic acid, propionic acid or the like.

Silver halide developing agents used for initiating development of theexposed sensitive element can be conventional types used for developingfilms or papers with the exception that a silver halide solvent orcomplexing agent such as sodium thiosulfate, sodium thiocyanate, ammoniaor the like is present in the quantity required to form a soluble silvercomplex which diffuses imagewise to the receiving support. Usually, theconcentration of developing agent and/or developing agent precursoremployed is about 3 to about 320 mg./ft of support.

Developing agents and/or developing agent precursors can be employed ina viscous processing composition containing a thickener such ascarboxymethyl cellulose or hydroxyethyl cellulose. A typical developercomposition is disclosed in US. Pat. No. 3,120,795 of Land et al. issuedFeb. 11, 1964.2

Developing agents and/or developing agent precursors can be employedalone or in combination with each other, as well as with auxiliarydeveloping agents. Suitable silver halide developing agents anddeveloping agent precursors which can be employed include, for example,polyhydroxybenzenes, alkyl substituted hydroquinones, as exemplified byt-butyl hydroquinone, methyl hydroquinone and 2,5-dimethylhydroquinone,catechol and pyrogallol; chloro substituted hydroquinones such aschlorohydroquinone or dichlorohydroquinone; alkoxy substitutedhydroquinones such as methoxy hydroquinone or ethoxy hydroquinone;aminophenol developing agents such as 2,4-diaminophenols andmethylaminophenols. These include, for example, 2,4- diaminophenoldeveloping agents which contain a group in the six position, and relatedamino developing agents, e.g.:

6-methyl-2,4-diaminophenol 6-methoxy-2,4-diaminophenol6ethyl-2,4-diaminophenol 6-phenyl-2,4-diaminophenol 6-paratolyl-2,4-dirninophenol 6-chloro-2,4-diaminophenol6-morpholinomethyl-Z,4-diaminophenol 6-piperidino-2,4-diaminophenol3,6-dimethyl-2,4-diaminophenol 6-phenoxy-2,4-diaminophenol2-methoxy-4-amino-5-methyl phenol 4-aminocatechol 4-aminoresorcinol2,4-diaminoresorcinol methyl-3,4-diaminophenol methoxy-3,4-diaminophenolmethyl-2,5-diaminophenol methoxy-2,S-diaminophenol methyl- 1,2,4-triamino benzene methoxy-l ,2,4triamino benzene p-hydroxyphenylhydrazine p-hydroxyphenyl hydroxylamine The aminophenol developingagents can be employed as an acid salt, such as hydrochloride or sulfatesalt.

Other silver halide developing agents include ascorbic acid, ascorbicacid derivatives, ascorbic acid ketals, such as those described in USPat. No. 3,337,342 of Green issued Aug. 22, 1967; hydroxylamines such asN,N-di(2-ethoxyethyl)hydroxylamine; 3-pyrazolidone developing agentssuch as l-phenyl- 3-pyrazolidone, including those described in KodakBritish Pat. No. 930,572 published July 3, 1963; and acyl derivatives ofp-aminophenol such as described in Kodak British Pat. No. 1,045,303published Oct. 12, 1966; pyrimidine developing agents, such as4-amino-5,6-dihydroxy-2-methyl pyrimidine; and aminomethyl hydroquinonesilver halide developing agents, such as 2-methyl-5-pyrrolidinomethylhydroquinone, 2-methyl-5-morpholinomethyl hydroquinone, and 2-methyl-5-piperidinomethyl hydroquinone. The aminomethyl hydroquinone silverhalide developing agents are especially suitable incorporated in thenegative photographic element.

Another suitable silver halide developing agent which can be used in thepractice of the invention is a reductone silver halide developing agent,especially an anhydro dihydro amino hexose reductone silver halidedeveloping agent, such as anhydro dihydro piperidino hexose reductone,anhydro dihydro pyrrolidino hexose reductone, and/or anhydro dihydromorpholino hexose reductone.

The described reductone silver halide developing agents can be preparedas described in US Pat. No. 2,936,308 of Hodge, issued May 10, 1960 andin an article by F. Weygand et al., Tetrahedron, Volume 6, pages 123-138(1959). Typically the described anhydro dihydro amino hexose reductonecompounds are prepared from the corresponding anhydro amino hexosereductones by hydrogenation in the presence of a suitable hydrogenationcatalyst, such as Raney nickel catalyst. The reductone silver halidedeveloping agent can be employed in various locations in the diffusiontransfer system, but is especially suitable in the processingcomposition. These can be used alone or in combinations of developingagents. These developing agents provide little or no stain and improvedstability.

Lactone derivative silver halide developing agents which have theproperty of forming a lactone silver halide developing agent precursorunder neutral and acid conditions are particularly useful. Typicallactone derivatives are described in copending US. Applications Ser.Nos. 764,348 and 764,301 filed Oct. 1, 1968, both entitled PhotographicCompositions and Processes in the name of Oftedahl. The particularlysuitable lactone derivatives provide desired developing activity andreduction of stain without adversely affecting desired maximum density,minimum density, photographic speed and other desired sensitometricproperties. Suitable lactone derivative developing agents include thosewhich under neutral, slightly alkaline or acid conditions, i.e., whenthe pH is lowered to a level of about 9 or lower, i.e., about 2 to about9, do not have significant developing activity, if any, due to formationof a developing agent precursor.

The developer solution and/or activator solution may contain additivessuch as toners, potassium iodide, or the like. For instance, a tonersuch as the toners described herein may be used.

Silver halide emulsions employed with receiving layers and elements ofthis invention can contain incorporated addenda, including chemicalsensitizing and spectral sensitizing agents, coating agents,antifoggants and the like. They can also contain processing agents suchas silver halide developing agents and/or developing agent precursors.Of course, the processing agents can be incorporated in a layer adjacentto the: silver halide emulsion if desired.

The photographic emulsions employed can also be x-ray or othernon-spectrally sensitized emulsions or they can contain spectralsensitizing dyes such as described in U.S. Pat. Nos. 2,526,632 ofBrooker et al. issued Oct. 24, i950 and 2,503,776 of Sprague issued Apr.11, 1950. Spectral sensitizers which can be used include cyanines,merocyanines, styryls and hemicyanines.

The photographic emulsions can contain various photographic addenda,particularly those known to be beneficial in photographic compositions.Various addenda and concentrations to be employed can be determined bythose skilled in the art. Suitable photographic addenda includehardeners, e.g., those set forth in British Pat. No. 974,317; bufferswhich maintain the desired developing activity and/or pH level; coatingaids; plasticizers, speed increasing addenda, such as amines, quaternaryammonium salts, sulfonium salts and alkylene oxide polymers; and variousstabilizing agents, such as sodium sulfrte. The photographic silver saltemulsions can be chemically sensitized with compounds of the sulfurgroup such as sulfur, selenium and tellurium sensitizers, noble metalsalts such as gold, or reduction sensitized with reducing agents orcombinations of such materials.

Various photographic silver salts can be used in the practice of theinvention. These include photographic silver halides such as silveriodide, silver bromide, silver chloride, as well as mixed halides suchas silver bromoiodide, silver chloroiodide, silver chlorobromide andsilver bromochloroiodide. Photographic silver salts which are not silverhalides can also be employed such as silver salts of certain organicacids, silver-dye salts or complexes, etc.

The photographic silver salts are typically contained in an emulsionlayer comprising any binding materials suitable for photographicpurposes. These include natural and synthetic binding materialsgenerally employed for this purpose, for example, gelatin, colloidalalbumin, water-soluble vinyl polymers, mono and polysaccharides,cellulose derivatives, proteins, water-soluble polyacrylamides,polyvinyl pyrrolidone and the like, as well as mixtures of such bindingagents. The elements can also contain release layers and/or antistaticlayers (i.e. conducting layers).

Release agents can be used either on the surface of the silver halideemulsion layer, on the receiving layer containing the nuclei in thereceiving layer containing the nuclei, or can be contained in thedeveloping or processing solutions. When added to the processingsolution in concentrations of about 3 percent to about 10 percent, byweight, the release agents prevent the processing solution from stickingto the receiver. Suitable release agents normally are used which have acomposition different from the binder used in the silver halideemulsion.

Among the release agents which may be used are the following: materialsrepresented by the following general formula normally used as the freeacid or anhydride or converted to a convenient salt such as the sodiumor ammonium:

flail r t i l Us. 35

may be used:

I 7 GH2--C w CHCH Q l (0:4. 0:0)

NH- :0 I O y H x n X n onht ln CHCH o N o o T x on on -CHT-(I'JH LOB-CH(l o o o o\ o 0 CH3 x OH \OH y n oin-0H) OH OH y n CHz-CH CH CH- o iOCHZCN x \OH ONa y 11 CHrCH- -oH cH l. l o o\ /o o o 0 y OH x nmaterials represented by the following general formula:

in which R is chosen from among H, and the lower alkyls such as CH C l-lC l-l x, y and n are whole integers.

R is chosen from among OH, O-alkyl, NH and NHR where R can be alkyl,substituted alkyl, phenyl, a fivemembered heterocyclic ring or asix-membered heterocyclic ring.

Particularly useful materials are the following:

i CHZCHQSCHZ y n Especially useful materials are resinous materialshaving molecular weights of about 10,000 to about 500,000 as describedin US. Pat. Nos. 3,169,946; 3,007,901; 3,206,312; 3,260,706; 2,306,071;and 3,102,028. These materials are lactones of resinous heteropolymersof a vinyl or isopropenyl organic acid tester of an unsaturatedaB-dicarboxylic acid reacted with a member selected from the groupconsisting of a monohydric alcohol and a mixture of a monohydric hydroxyacid and a monohydric alkanol.

Coatings of these agents are relatively thin, having a preferredcoverage of about 6.0 mg./ft However, a useful range may be from 1.0 mg.to 1.0 g./ft It will also be understood that a release agent can beincorporated in the receiving layer along with the nuclei and/or binderused as a carrier for the nuclei.

The following examples are included for a further understanding of theinvention:

EXAMPLE 1 A nuclei melt is prepared as follows:

1. 138 grams of 10 percent bone gelatin in 862 ml. of

distilled water.

2. heat to 50 C. and add 7 ml. of 1.24 percent PdCl solution (1 percentHCl).

3. Adjust pH to 6.0 with sodium hydroxide.

4. Add 30 ml. of 0.2 percent NaBH solution (60 mg.) to react with thePdCl to form colloidal palladium (pH should rise to 8.3 8.5).

5. Stir 10 minutes at 50 C. and adjust pH to 5.5 with 0.1 N

HCl.

6. Add 562 g. of 10 percent bone gelatin and 438 ml. of

distilled water.

7. Stir and chill set.

Coatings using this nuclei melt are as follows:

Coatings Efieet on Tone 1 2 3 4 5 Nuclei melt, m1 48 48 48 48 48Distilled water. 250 252 252 250 252 1% Polymer 1""... 5 5 5 5 5 10%Formaldehyde 2. 5 2. 5 2. 5 2. 5 2. 5 15% Saponln 3 3 3 3 3 10%Potassium iodide"... 1.3 1.3 1,3 0.2% Silver nitrate 5 5 1%1-phenyl-5-selen0-1,2,3,4-tetrazol 1.0 1 0 1.0 1.0

Sodium salt of carboxy butyl esterlactone of the interpolymer of maleicanhydroXide-vinyl acetate (11.27% by weight) 29 ml, Distilled water 500ml. Methanol 2250 ml.

Each receiver sheet is tested by placing in contact with a silverbromoiodide emulsion coated on opaque support, exposed, and developed bymeans of rupture of a viscous pod of the following formulation:

gll

-methyl-Z.4-diaminophenol sulfate 5-10 ter-Butyl Hydroquinone 25 Na,S,OH,O 6O NaOl-l 20 KOH 20 Kl 0.6-1.6 Hydroxy ethyl cellulose 3-4.5 7r K 5025-50 Results;

Coating Dmax. Tone l 1.60 Cold 2 1.36 Cold 3 1.48 Warm 4 1.12 Neutral 51.10 Neutral EXAMPLE 2 Receiver sheets are prepared as in Example Icoating 1, except that instead of l-phenyl-S-seleno-l ,2,3,4-tetrazole,other tetrazoles are employed. After processing the receiving sheetsaccording to Example l, the washed samples are placed in a sealedchamber for six days at l F 85 percent R.H., 1,800 foot candles of whitelight using fluorescent lamps. The following results are obtained:

The reference to toe steps concerns a conventional H and Dcharacteristic curve for a silver halide emulsion having increments of0. l 5 log E or an increment ofO. l 5 log E for one step.

EXAMPLE 3 Example l is repeated with l-allyl-S-seleno-l,2,3,4- tetrazolesubstituted in coating 5 for l-phenyl-S-selenol,2,3,4-tetrazole. Aneutral tone is obtained.

EXAMPLE 4 5 Selenol ,2,3,4-tetrazoles having the structure t :N W 747 inwhich R is methyl, ethyl, butyl or decyl, phenyl, or tolyl are employedas toners in a diffusion transfer process as described in Example 1,coating 5. A neutral tone results in each instance.

The invention has been described in detail with particular reference topreferred embodiments thereof, but, it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

I claim:

1. A receiving element comprising a support having thereon an alkalipermeable organic colloid layer containing a silver precipitant and aS-selenol ,2,3,4-tetrazole.

2. A receiving element of claim 1 in which said organic colloid iselatin.

3. 1% receiving element of claim 1 in which said silver precipitant is acolloidal noble metal.

4. A receiving element of claim 1 which also contains a silver halidesolvent.

5. A receiving element of claim 1 which also contains a silver halidedeveloping agent.

6. A receiving element of claim 1 in which said tetrazole isl-phenyl-S-seleno-l ,2,3 ,4-tetrazole.

7. A receiving element of claim 1 in which said tetrazole is1-allyl-5-seleno-1,2,3,4-tetrazole.

8. A photographic element of claim 1 which contains over said organiccolloid layer a light-sensitive silver halide emulsion layer.

9. A receiving element of claim 1 in which said seleno tetrazolecomprises about 0.01 mg. to about 0.5 g. per square foot.

10. In a process of obtaining an image from undeveloped areas of anexposed developing silver halide emulsion layer to a reception layercontaining a silver precipitant, the improvement which comprisescarrying out the development of the silver halide layer in the presenceof a 5-seleno-l,2,3,4- tetrazole.

11. A photographic process according to claim 10 wherein the selenotetrazole is a l-phenyl-S-selenol ,2,3,4-tetrazole.

12. A photographic process according to claim 10 in which the receptionlayer comprises a 5-seleno-l,2,3,4-tetrazole toning agent.

13. A process of claim 10 in which said silver precipitant is a noblemetal.

14. A photographic element comprising a silver image in a proteinaceousreceiving layer on a support, said image obtained by a diffusiontransfer process, said receiving layer comprising a5-seleno-1,2,3,4-tetrazole toning agent.

2. A receiving element of claim 1 in which said organic colloid isgelatin.
 3. A receiving element of claim 1 in which said silverprecipitant is a colloidal noble metal.
 4. A receiving element of claim1 which also contains a silver halide solvent.
 5. A receiving element ofclaim 1 which also contains a silver halide developing agent.
 6. Areceiving element of claim 1 in which said tetrazole is1-phenyl-5-seleno-1,2,3,4-tetrazole.
 7. A receiving element of claim 1in which said tetrazole is 1-allyl-5-seleno-1,2,3,4-tetrazole.
 8. Aphotographic element of claim 1 which contains over said organic colloidlayer a light-sensitive silver halide emulsion layer.
 9. A receivingelement of claim 1 in which said seleno tetrazole comprises about 0.01mg. to about 0.5 g. per square foot.
 10. In a process of obtaining animage from undeveloped areas of an exposed developing silver halideemulsion layer to a reception layer containing a silver precipitant, theimprovement which comprises carrying out the development of the silverhalide layer in the presence of a 5-seleno-1,2,3,4-tetrazole.
 11. Aphotographic process according to claim 10 wherein the seleno tetrazoleis a 1-phenyl-5-seleno-1,2,3,4-tetrazole.
 12. A photographic processaccording to claim 10 in which the reception layer comprises a5-seleno-1,2,3,4-tetrazole toning agent.
 13. A process of claim 10 inwhich said silver precipitant is a noble metal.
 14. A photographicelement comprising a silver image in a proteinaceous receiving layer ona support, said image obtained by a diffusion transfer process, saidreceiving layer comprising a 5-seleno-1,2,3,4-tetrazole toning agent.